scholarly journals Spectroscopic Fourth-order Coronagraph for the Characterization of Terrestrial Planets at Small Angular Separations from Host Stars

2021 ◽  
Vol 161 (2) ◽  
pp. 83
Author(s):  
Taro Matsuo ◽  
Satoshi Itoh ◽  
Yuji Ikeda
Keyword(s):  
Fourth Order ◽  
Terrestrial Planets ◽  
Host Stars

scholarly journals Asteroseismic potential of CHEOPS

2018 ◽  
Vol 620 ◽  
pp. A203 ◽  
Author(s):  
A. Moya ◽  
S. Barceló Forteza ◽  
A. Bonfanti ◽  
S. J. A. J. Salmon ◽  
V. Van Grootel ◽  
...  
Keyword(s):  
Time Series ◽  
Main Sequence ◽  
Uncertainty Reduction ◽  
Light Curves ◽  
Accuracy And Precision ◽  
Mass Uncertainty ◽  
The Impact ◽  
Host Stars

Context. Asteroseismology has been impressively boosted during the last decade mainly thanks to space missions such as Kepler/K2 and CoRoT. This has a large impact, in particular, in exoplanetary sciences since the accurate characterization of the exoplanets is convoluted in most cases with the characterization of their hosting star. In the decade before the expected launch of the ESA mission PLATO 2.0, only two important missions will provide short-cadence high-precision photometric time-series: NASA–TESS and ESA–CHEOPS missions, both having high capabilities for exoplanetary sciences. Aims. In this work we want to explore the asteroseismic potential of CHEOPS time-series. Methods. Following the works estimating the asteroseismic potential of Kepler and TESS, we have analysed the probability of detecting solar-like pulsations using CHEOPS light-curves. Since CHEOPS will collect runs with observational times from hours up to a few days, we have analysed the accuracy and precision we can obtain for the estimation of νmax. This is the only asteroseismic observable we can recover using CHEOPS observations. Finally, we have analysed the impact of knowing νmax in the characterization of exoplanet host stars. Results. Using CHEOPS light-curves with the expected observational times we can determine νmax for massive G and F-type stars from late main sequence (MS) on, and for F, G, and K-type stars from post-main sequence on with an uncertainty lower than a 5%. For magnitudes V <  12 and observational times from eight hours up to two days, the HR zone of potential detectability changes. The determination of νmax leads to an internal age uncertainty reduction in the characterization of exoplanet host stars from 52% to 38%; mass uncertainty reduction from 2.1% to 1.8%; radius uncertainty reduction from 1.8% to 1.6%; density uncertainty reduction from 5.6% to 4.7%, in our best scenarios.

Discovering the atmospheres of hot Jupiters

2019 ◽  
Vol 15 (S354) ◽  
pp. 467-472
Author(s):  
P. Wilson Cauley
Keyword(s):  
Detailed Characterization ◽  
Hot Jupiters ◽  
Short Period ◽  
The Future ◽  
To Come ◽  
Host Stars

AbstractHot Jupiters are an extraordinary class of exoplanets, orbiting their host stars with periods of hours to a few days. Some of these objects have day-side temperatures approaching photospheric temperatures of late K-type stars. I will give an overview of how we characterize the atmospheres of these fascinating objects and some the more recent exciting results to come from ground and space-based telescopes, as well as what the future holds for detailed characterization of short-period exoplanet atmospheres.

scholarly journals Direct Imaging of Planet Transit Events

2012 ◽  
Vol 8 (S293) ◽  
pp. 378-381
Author(s):  
Gerard T. van Belle ◽  
Kaspar von Braun ◽  
Tabetha Boyajian ◽  
Gail Schaefer
Keyword(s):  
Wavelength Dependence ◽  
Position Angle ◽  
Atmospheric Composition ◽  
Optical Interferometer ◽  
Direct Imaging ◽  
Stellar Radius ◽  
System Parameters ◽  
Optical Interferometers ◽  
Host Stars

AbstractExoplanet transit events are attractive targets for the ultrahigh-resolution capabilities afforded by optical interferometers. The intersection of two developments in astronomy enable direct imaging of exoplanet transits: first, improvements in sensitivity and precision of interferometric instrumentation; and second, identification of ever-brighter host stars. Efforts are underway for the first direct high-precision detection of closure phase signatures with the CHARA Array and Navy Precision Optical Interferometer. When successful, these measurements will enable recovery of the transit position angle on the sky, along with characterization of other system parameters, such as stellar radius, planet radius, and other parameters of the transit event. This technique can directly determine the planet's radius independent of any outside observations, and appears able to improve substantially upon other determinations of that radius; it will be possible to extract wavelength dependence of that radius determination, for connection to characterization of planetary atmospheric composition & structure. Additional directly observed parameters - also not dependent on transit photometry or spectroscopy - include impact parameter, transit ingress time, and transit velocity.

scholarly journals Characterization of extrasolar terrestrial planets from diurnal photometric variability

Nature ◽  
2001 ◽  
Vol 412 (6850) ◽  
pp. 885-887 ◽  
Author(s):  
E. B. Ford ◽  
S. Seager ◽  
E. L. Turner
Keyword(s):  
Terrestrial Planets ◽  
Photometric Variability

scholarly journals Comprehensive Census and Complete Characterization of Nearby Debris Disk Stars

2015 ◽  
Vol 10 (S314) ◽  
pp. 179-182
Author(s):  
Tara H. Cotten ◽  
Inseok Song
Keyword(s):  
Large Scale ◽  
Complete Characterization ◽  
High Resolution Spectroscopy ◽  
Debris Disks ◽  
Infrared Excess ◽  
History Of ◽  
Debris Disk ◽  
Host Stars ◽  
Comprehensive Study

AbstractDebris disks are intimately linked to planetary system evolution since the rocky material surrounding the host stars is believed to be due to secondary generation from the collisions of planetesimals. With the conclusion and lack of future large scale infrared excess survey missions, it is time to summarize the history of using excess emission in the infrared as a tracer of debris and exploit all available data as well as provide a comprehensive study of the parameters of these important objects. We have compiled a catalog of infrared excess stars from peer-reviewed articles and performed an extensive search for new debris disks by cross-correlating the Tycho-2 and AllWISE catalogs. This study will conclude following the thorough examination of each debris disk star's parameters obtained through high-resolution spectroscopy at various facilities which is currently ongoing. We will maintain a webpage (www.debrisdisks.org) devoted to these infrared excess sources and provide various resources related to our catalog creation, SED fitting, and data reduction.

scholarly journals A chromosome map to unveil stellar populations with different magnesium abundances. The case of ω Centauri

2020 ◽  
Vol 497 (3) ◽  
pp. 3846-3859
Author(s):  
A P Milone ◽  
A F Marino ◽  
A Renzini ◽  
C Li ◽  
S Jang ◽  
...  
Keyword(s):  
Globular Clusters ◽  
First Generation ◽  
Hubble Space Telescope ◽  
Stellar Populations ◽  
Stellar Content ◽  
Chemical Abundances ◽  
Chromosome Map ◽  
First Time ◽  
Host Stars

ABSTRACT Historically, photometry has been largely used to identify stellar populations [multiple populations (MPs)] in globular clusters (GCs) by using diagrams that are based on colours and magnitudes that are mostly sensitive to stars with different metallicities or different abundances of helium, carbon, nitrogen, and oxygen. In particular, the pseudo-two-colour diagram called chromosome map (ChM), allowed the identification and the characterization of MPs in about 70 GCs by using appropriate filters of the Hubble Space Telescope (HST) that are sensitive to the stellar content of He, C, N, O, and Fe. We use here high precision HST photometry from F275W, F280N, F343N, F373N, and F814W images of ω Centauri to investigate its MPs. We introduce a new ChM whose abscissa and ordinate are mostly sensitive to stellar populations with different magnesium and nitrogen, respectively, in monometallic GCs. This ChM is effective in disentangling the MPs based on their Mg chemical abundances, allowing us to explore, for the first time, possible relations between the production of these elemental species for large samples of stars in GCs. By comparing the colours of the distinct stellar populations with the colours obtained from appropriate synthetic spectra we provide ‘photometric-like’ estimates of the chemical composition of each population. Our results show that, in addition to first-generation (1G) stars, the metal-poor population of ω Cen hosts four groups of second-generation stars with different [N/Fe], namely, 2GA–D. 2GA stars share nearly the same [Mg/Fe] as the 1G, whereas 2GB, 2GC, and 2GD are Mg depleted by ∼0.15, ∼0.25, and ∼0.45 dex, respectively. We provide evidence that the metal-intermediate populations host stars with depleted [Mg/Fe].

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